question

You can refer to the following sample.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using PlayFab;
using PlayFab.ClientModels;
using PlayFab.EconomyModels;
using System.Text;
using UnityEngine.Networking;

public class UGCTest : MonoBehaviour
{
    void Start()
    {
        PlayFabClientAPI.LoginWithCustomID(new LoginWithCustomIDRequest
        {
            CustomId = " "
        },
        (result) =>
        {
            Debug.Log("login success");
        },
        (error) =>
        {
            Debug.LogError(error.GenerateErrorReport());
        });
    }

    string uploadUrl;
    string uploadId;
    string itemId;
    string payloadStr;
    byte[] payload;
    /// <summary>
    /// 1.CreateUploadUrls
    /// </summary>
    public void CreateUrl()
    {
        PlayFabEconomyAPI.CreateUploadUrls(new CreateUploadUrlsRequest
        {
            Files = new List<UploadInfo>
            {
                new UploadInfo
                {
                    FileName="test.txt"
                }
            }
        }, CreateUrlsSuccess, OnError);
    }

    public void CreateUrlsSuccess(CreateUploadUrlsResponse result)
    {
        uploadUrl = result.UploadUrls[0].Url;
        uploadId = result.UploadUrls[0].Id;
        Debug.Log(result.UploadUrls[0].FileName + ":" + result.UploadUrls[0].Id + ":" + result.UploadUrls[0].Url);
    }

    /// <summary>
    /// 2.upload
    /// </summary>
    public void Upload()
    {
        ResourcesFile();
        StartCoroutine(Upload_Put());
    }

    IEnumerator Upload_Put()
    {
        UnityWebRequest request = UnityWebRequest.Put(uploadUrl, payload);
        request.SetRequestHeader("Content-Type", "text/plain");
        request.SetRequestHeader("comp", "blob");
        request.SetRequestHeader("x-ms-blob-type", "blockblob");
        yield return request.SendWebRequest();
        if(request.result==UnityWebRequest.Result.ProtocolError||request.result==UnityWebRequest.Result.ConnectionError)
        {
            Debug.LogError(request.error);
        }
        else
        {
            Debug.Log("put success");
        }
    }

    /// <summary>
    /// 3.CreateDraftItem
    /// </summary>
    public void CreateDraft()
    {
        PlayFabEconomyAPI.CreateDraftItem(new CreateDraftItemRequest
        {
            Publish = false,
            Item = new PlayFab.EconomyModels.CatalogItem
            {
                Type = "ugc",
                Title = new Dictionary<string, string>
                {
                    {
                        "neutral","UGCTest"
                    }
                },
                Description = new Dictionary<string, string>
                {
                    {
                        "neutral","A ugc item"
                    }
                },
                ContentType = "example item",
                IsHidden = false,
                Contents = new List<Content>
                {
                    new Content
                    {
                        Id=uploadId,
                        Url=uploadUrl
                    }
                }
            }
        },
        (result) =>
        {
            itemId = result.Item.Id;
            Debug.Log(result.Item.Id + ":" + result.Item.Contents[0].Id + ":" + result.Item.Contents[0].Url);
        }, OnError);
    }

    /// <summary>
    /// 4.Publish
    /// </summary>
    public void Publish()
    {
        PlayFabEconomyAPI.PublishDraftItem(new PublishDraftItemRequest
        {
            Id = itemId
        },
        (result) =>
        {
            Debug.Log("Publish Success");
        }, OnError);
    }

    /// <summary>
    /// 5.GetStatus
    /// </summary>
    public void GetPublishStatus()
    {
        PlayFabEconomyAPI.GetItemPublishStatus(new GetItemPublishStatusRequest
        {
            Id = itemId
        },
        (result) =>
        {
            Debug.Log(result.StatusMessage + ":" + result.Result);
        }, OnError);
    }

    public void OnError(PlayFabError error)
    {
        Debug.LogError(error.GenerateErrorReport());
    }

    public void ResourcesFile()
    {
        TextAsset txt = Resources.Load("test") as TextAsset;
        payloadStr = txt.text;
        payload = Encoding.UTF8.GetBytes(payloadStr);
    }
}